This is necessary for GtkNotebook so that the stack is always drawn
before the header.
And that is necessary so that the active tab can use negative
margins to overdraw the border of the stack to create a gap and
simulate old GTK2-style visuals for notebooks.
:active is reserved for "mouse button down on node", so we have to use
something else. And stack switcher and radio buttons use :checked for
the active widget, so it makes sense to use :checked for the active tab,
too.
Themes have been adapted.
TODO: Implement :active for tabs.
Sometimes default tab labels ("Page <n>") get created on-demand,
and in that case, we were forgetting to put them below the tab
node in the CSS node tree. The visible result of this is that the
heuristics for when to give notebooks background in Adwaita fail
in some cases. So, make sure to always place the label below the
tab node.
Always have Since: annotations at the very bottom, use the correct
ClassName::signal-name/ClassName:property-name syntax, fix a few typos
in type names, wrong function names, non-existing type names, etc.
Button state was being kept in two separate variables, which lead
to slight confusions in DnD that caused the notebook to ignore the
first click after DnD happened from (within) it. Unify these two
into one, which helps us keep better track of the really pressed
buttons.
Move code to properly reinsert the tab label to where it belongs.
The if has the distinction between reparented-to-dnd-window and
just-changed-the-gdk-window-to-draw-to right there.
https://bugzilla.gnome.org/show_bug.cgi?id=760754
Use gtk_box_gadget_reverse_children and gtk_css_node_reverse_children
to flip the children of the header_gadget and the tabs_gadget when
appropriate.
Add new CSS node tests to verify that the node order is updated
as expected in all cases.
So far, the box gadget is always allocating all children the
full size in the cross axis. This behavior corresponds to the
align-items: stretch behavior in
https://www.w3.org/TR/css-flexbox-1/#align-items-property
This commit implements the other modes described there.
While widgets have halign/valign properties that we can use for
this, the API for inserting gadgets has to change to take an
extra align parameter. All callers have been updated to pass
GTK_ALIGN_FILL, since that corresponds to the previous behavior.
https://bugzilla.gnome.org/show_bug.cgi?id=760668
When a tab drag starts, we need to move the tab label into the drag
window via gtk_widget_set_parent_window().
If we don't unparent, but just unrealize the widget, we don't lose the
cssnode position.
GtkNotebook does not switch the current page if all pages are hidden. So
it may be that no visible page exsits, but there still is a current
page set.
We culd clear the current page, but I'm unsure about backwards
compatibility.
So instead, this new function handles that case.
This allows reworking the content node to do real height-for-width.
The content node also takes care of border width, but we might want to
have the toplevel do it or just get rid of it.
